Focusing on intracranial aneurysms, a study by Aoki et al. found that human IA tissues had greater staining of COX2 compared to controls and that in a rat model of IA, there was a significant increase in COX2 mRNA and protein in cerebral artery tissue, 3 months after induction of aneurysm (p < 0.01) [45]. This evidence concerns the gene PTGS2 and Dilatation of the cerebral artery.